Method: The universal composites used in the experiments are: EsthetX HD A2 (lot#1106201, Dentsply); TPH 3 A3.5 (lot# 1102131, Dentsply) ; Filtek Z100 A2 (lot# 8GN, 3M); Filtek Z250 A2 (lot# N269383, 3M); Filtek Xtra A2 (lot# N276480, 3M); Venus Diamond BL (lot# 010022, Heareus); Herculite Ultra A2E (lot# 3707940, Kerr) and Tetric EvaCeram A2 (lot#P02083, Ivaclar). AElite LS Packabe A2 (lot# 1100004101, Bisco). The stiffness of composites was measured by TA XT Plus Texture Analyzer. A 1.7 gram of composite was dispensed into a hole (φ16mm x 4 mm) drilled in a stainless steel plate which was kept in an environmental chamber with constant temperature of 23o C . The excess amount of composite was removed by a Teflon spatula to make the paste surface even. The cylinder probe (φ 4 mm ) aligned with the center of the hole started to approach the paste at 5.0 mm/s (pre-test Speed) until a 20.0 grams trigger force was detected. The probe then began to compress the paste with a speed of 0.5 mm/s and traveled down a distance of 3 mm. The curve of force vs time was recorded. The slope (gradient) of the curve between 3.5 and 4 seconds was used as an indication of stiffness. Means comparisons for all pairs using one way ANOVA Tukey’s test were applied for data analysis at a confidence level of 95%.
Result:
Glass Ionomers |
Stiffness |
||
Mean (Kg/sec x 0.01) |
Stdev (Kg/sec x 0.01) |
Group |
|
Esthet-X HD |
12.7 |
0.9 |
A |
Venus Diamond |
11.8 |
1.0 |
A |
Filtek Z250 |
9.9 |
0.5 |
B |
Tetric EvaCeram |
8.9 |
0.3 |
B, C |
Herculite Ultra |
7.5 |
0.4 |
C, D |
AElite LS |
6.9 |
0.3 |
D |
TPH3 |
4.6 |
0.4 |
E |
Filtek Supre Xtra |
3.8 |
0.6 |
E |
Filtek Z100 |
1.7 |
0.3 |
F |
Conclusion: A wide range of stiffness was found among the nine tested universal composites. Esthet-X HD Venus Diamond and Filtek Z250 exhibited the highest stiffness, while TPH3, Filtek Supre Xtra and Filtek Z100 exhibited the lowest stiffness. Differences in stiffness has a direct influence over the clinician’s preference for composite handling properties during placement.
Keywords: Composites and stiffness